A wide variety of communications takes place over a network. Many of these take place without connecting wires, such as in cellular communication systems.
It is often desirable to operate the transmitters in a wireless communication system at very low power. This may reduce the drain on the power supply, which may be a battery with a limited life. Lowering the transmission power level may also help reduce interference between multiple transmitters operating at the same time in nearby locations.
Unfortunately, transmitting at low power can often times have a drawback—it may be difficult to receive the transmitted signal over great distances.
Cellular networks often address this issue by installing base stations at numerous, strategic locations. These base stations may receive transmissions from local cell phones or other nodes and forward these transmissions to more distant locations.
Unfortunately, it can be costly to install and maintain base stations at all of the strategic locations at which they may be needed. The locations at which base stations are needed, moreover, may not always be known, due to the mobile nature of a cell phone. This can make full coverage even more difficult.
Ultra Wide Band (UWB) is a new technology that may allow numerous transmitters to operate at the same time and in the same band, without interfering with one another or with existing communication systems also operating within the same band. Many radio frequency (“RF”) technologies use a carrier modulated only within a relatively narrow band to transmit information. UWB, on the other hand, sends pulses of energy across a broad spectrum of frequencies. Using this wideband technique, a UWB signal can be successfully transmitted at such a low power level that it can often exist in the same band as more narrow band RF technologies without significantly interfering with those narrow band transmissions.
Unfortunately, the transmission distance of UWB is also limited, particularly when the power level of the signal is low.
A typical communicating node on a network both transmits and receives information. Performing both operations at the same time is known as “full duplex” operation. Switching between the operations is known as “half duplex” operation.
Full duplex operation can create technical challenges. For example, full duplex operation may require twice the bandwidth that half duplex operation requires. Full duplex operation with wireless nodes may also create signal processing challenges. The close proximity of the transmitter to the receiver may result in the signal from the transmitter being so strong at the receiver as to overload the receiver.
Half duplex operation, on the other hand, may present a different type of technological challenge. With half duplex operation, the transmitting node must have some way of determining when the receiving note will be receiving to insure that its transmission is received.
Centralized traffic management is often employed to fill this technological need with half duplex operation. However, centralized traffic management may require numerous base stations and thus suffer from many of the same problems as wireless network systems that rely upon a network of base stations.